title: Synchrony in Parkinson's disease: importance of intrinsic properties of the external globus pallidus.
abstract: The mechanisms for the emergence and transmission of synchronized oscillations in Parkinson's disease, which are potentially causal to motor deficits, remain debated. Aside from the motor cortex and the subthalamic nucleus, the external globus pallidus (GPe) has been shown to be essential for the maintenance of these oscillations and plays a major role in sculpting neural network activity in the basal ganglia (BG). While neural activity of the healthy GPe shows almost no correlations between pairs of neurons, prominent synchronization in the β frequency band arises after dopamine depletion. Several studies have proposed that this shift is due to network interactions between the different BG nuclei, including the GPe. However, recent studies demonstrate an important role for the properties of neurons within the GPe. In this review, we will discuss these intrinsic GPe properties and review proposed mechanisms for activity decorrelation within the dopamine-intact GPe. Failure of the GPe to desynchronize correlated inputs can be a possible explanation for synchronization in the whole BG. Potential triggers of synchronization involve the enhancement of GPe-GPe inhibition and changes in ion channel function in GPe neurons.
authors.affiliation: Applied Analysis and Mathematical Physics, MIRA Institute of Technical Medicine and Biomedical Technology, University of Twente Enschede, Netherlands ; Biomedical Signals and Systems, MIRA Institute of Technical Medicine and Biomedical Technology, University of Twente Enschede, Netherlands.
authors.forename: Bettina C
authors.initials: BC
authors.lastname: Schwab
authors.forename: Tjitske
authors.initials: T
authors.lastname: Heida
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Enrico
authors.initials: E
authors.lastname: Marani
authors.forename: Stephan A
authors.initials: SA
authors.lastname: van Gils
authors.forename: Richard J A
authors.initials: RJ
authors.lastname: van Wezel
keywords: GPe-GPe synapses; HCN channels; NaF channels; SK channels; desynchronization; dopamine depletion; external globus pallidus; plasticity